The present invention relates to a coin sorting method and a device, and more particularly to a coin sorting method and a device capable of preventing the acceptance of foreign coins, counterfeit coins and the like which have very similar materials and outer shapes to authentic ones.
Generally, a coin sorting device for use in automatic vending machines, money-changing machines, self-service machines and the like is configured to accept coins by sorting the coins slotted through a coin insertion slot into authentic ones and counterfeit ones and sorting the authentic coins according to the denominations.
Coins are sorted according to results obtained by detecting features such as material and outer shape of the coins by means of a sensor located on a coin passage for guiding the coins slotted through the coin insertion slot to a coin sorting part.
The sensor for detecting the features of the coins is, for example, a sensor which has a coil disposed on one side of the coin passage and forms an oscillation circuit including this coil. This sensor makes use of a change in inductance of the coil caused by the coins as they pass by the coil to detect a change in oscillation frequency, thereby obtaining information about the coins passed by the coil.
There is also another sensor which is configured to have an oscillation coil, which is excited by an exciting current having a predetermined frequency, disposed on one side of the coin passage and a reception coil disposed on the other side of the coin passage. This structure makes use of a change in mutual coupling factor (magnetic coupling factor) between the oscillation coil and the reception coil as the coins pass between the oscillation coil and the reception coil and detects a change in output voltage of the reception coil to obtain data about the coins passed between them.
The inductance and the mutual coupling factor which are variable as the coins pass between the coils as described above are different depending on the materials of coins. Therefore, the material of coins can be detected from the output of either of the above sensors. And, when the oscillation frequency or the exciting frequency is low, the material of the surface of the coin can be detected, and when the oscillation frequency or the exciting frequency is high, the material of the inside of the coin can be detected.
It is also possible to detect the outer shape of a coin by adjusting the position of the sensor disposed on the coin passage. This detection makes use of a difference in output depending on coins passing by the sensor with the sensor positioned at a predetermined height because the coins passing through the coin passage have a different height (area) depending on their diameters.
Conventional coin sorting devices generally have the aforesaid sensors in order to detect the material and outer shape of coins and are provided with a single or plurality of sensors for respective uses.
But, the conventional coin sorting devices identify slotted coins as authentic or counterfeit according to their material and outer shape and often accept foreign coins as authentic, because they have very similar material, and outer shape to authentic coins. Actually, many crimes are committed by taking advantage of such a weak point of the coin sorting devices these days.
In view of the circumstances described above, it is an object of the present invention to provide a coin sorting method and a device which can detect counterfeit coins such as foreign coins having very similar material, outer shape and the like to authentic ones.
To achieve the aforesaid object, the invention of claim 1 is a coin sorting method in which a sensor is disposed on a coin passage, features of coins rolling through the coin passage are detected by the sensor, the coins are identified as authentic or counterfeit on the basis of the detected results, the coins identified as authentic by the identification are accepted, and the coins identified as counterfeit by the identification are returned, characterized by:
measuring a feature detection time during which the sensor detects the features of the coins;
comparing the measured feature detection time with a predetermined time; and identifying the coins as authentic or counterfeit on the basis of the compared results.
The invention of claim 2 is the coin sorting method according to claim 1, wherein the output of the sensor is an output including change points which change from rising to falling and from falling to rising depending on a pattern of the coin, and the feature detection time is a time required between the detection of a first change point and the detection of a last change point among the change points.
The invention of claim 3 is the coin sorting method according to claim 1, wherein a ratio between a presence detection time during which the sensor detects the presence of the coin and the feature detection time is calculated, and the coin is identified as authentic or counterfeit according to the compared result between the calculated value and predetermined judgment values.
And, the invention of claim 4 is a coin sorting device having a sensor disposed on a coin passage, which detects features of coins rolling through the coin passage by the sensor, identifies the coins as authentic or counterfeit on the basis of the detected results, accepts the coins identified as authentic by the identification, and returns the coins identified as counterfeit by the identification, characterized in that the coin sorting device comprises:
feature sensing means for detecting the features of the coin on the basis of an output of the sensor;
time measuring means for measuring a feature detection time during which the feature sensing means detects the features of the coin; and
comparison means for comparing the feature detection time measured by the time measuring means with a predetermined time.
The invention of claim 5 is the coin sorting device according to claim 4, wherein the output of the sensor is an output including change points which change from rising to falling and from falling to rising depending on a pattern of the coin;
the feature sensing means detects the change points from the output of the sensor; and
the time measuring means measures a time required between the detection of a first change point and the detection of a last change point among the change points by the feature sensing means.
The invention of claim 6 is the coin sorting device according to claim 4, further comprising time ratio calculation means for calculating a ratio between a presence detection time during which the sensor detects the presence of the coin and the feature detection time, wherein the comparison means compares a value calculated by the time ratio calculation means with predetermined judgment values.